U.S. Pat. No. 3,480,622 discloses a process for debromination of a 9.alpha.-bromo-11.beta.-hydroxy steroid by reaction with a salt of a polyvalent metal (Cr) which is in a lower state of valence (+2) capable of being oxidized to a higher state (+3) in the presence of a substance (thiol) capable of providing hydrogen radicals. The reducing agent was preferably a chromous salt of an organic carboxylic acid, preferably chromous acetate. Listed as suitable to provide hydrogen radicals were a number of substances, including thiols which could carry various substituents including carboxyl groups. However, it was preferred that the substituent be lower alkyl or unsubstituted aryl groups such as phenyl. A mechanistic explanation for the above is set forth in Tetrahedron Letters 43, 3151 (1964) and a more detailed account is found in J. Am. Chem. Soc. 88, 3016 (1966).
J. Fried and E. F. Sabo in J. Am. Chem. Soc. 79, 1130 (1957) discussed the problems of trying to debrominate a 9.alpha.-bromo-11.beta.-hydroxy steroid to form the corresponding 11.beta.-hydroxy steroid. Using chromous chloride and zinc in acetic acid, they obtained the pure 9(11)-dehydro compound in about 80% yield, page 1131.